Gas ring for fuel burner

ABSTRACT

A gas ring for fuel burners having a burner throat, the ring having an inside diameter substantially the same as that of the throat and having a peripherally spaced set of elongated nozzles or fingers extending radially (inward) from the ring. The fingers have discharge openings in at least one side and are oriented to discharge gas well within the air stream in said burner throat at various angular positions to which they may be adjusted. Such fingers may be used alone or in conjunction with conventional gas exit orifices spaced around the inner periphery of the ring.

United States Patent 1111 3,568,934

[72] Inventor John Dunn [56] References Cited Montvale, NJ. UNITEDSTATES PATENTS [21] P 7973? 969 824,972 7/1906 Borne 239/567 [22] d 3" 32,834,405 5/1958 Voorheis 431/176 [451 P t E C 3,179,152 4/1965Musatetal. 431/176 [73] Assgnee Y gmeemg 3,314,611 4/1967 McCartney m1.239/601X ew York, N.Y.

. Primary Examiner-Lloyd L. King Attorney-Nathaniel L. Leek ABSTRACT: Agas ring for fuel burners having a burner throat, the ring having aninside diameter substantially the same as that of the throat and havinga peripherally spaced set [54] F ES? of elongated nozzles or fingersextending radially (inward) alms rawmg from the ring. The fingers havedischarge openings in at least [52] U.S. Cl 239/567, one side and areoriented to discharge gas well within the air 239/60l,431/176 stream insaid burner throat at various angular positions to [51] Int. Cl 805!)1/18 which they may be adjusted. Such fingers may be used alone [50]Field of Search 239/56, 7, or in conjunction with conventional gas exitorifices spaced around the inner periphery of the ring.

' PATENTEDHAR 919?: 3.568834 7 sum 1 0F 2 INVENTOR JOHN DUNN I I Y BYATTCR NEY PATENTED MAR 9 I97! SHEET 2 [IF 2' FIG.

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INVENTOR JOHN DUNN ATTORNEY ans have run FUEL BURNER This inventionrelates to gas burners and more particularly to gas rings of the typeused in connection with industrial burners, said burners having a burnerthroat coaxial with the prin' cipal axis of said ring.

An object is to provide a gas ring of the above type having novel andimproved gas discharge elements adapted to provide an improved gas airmixture and stable operation under varying loads and varying conditionsof flow of combustion air even with low gas pressure in said ring.

Another object is to provide a gas ring of the above type which permitson-the-job variation of the gas supply to different parts of a burnerthroat.

Another object is to provide a burner of the above type having novel andimproved details of construction and features of operation.

Various other objects and advantages will be apparent as the nature ofthe invention is more fully disclosed.

The present invention is designed to overcome certain disadvantages ofthe conventional ring-type gas burner when operating at a low gaspressure (which is nearly always the case when the burner is operatingat the lower end of a load range) especially when the inside diameter ofthe gas ring and burner throat are substantial; for example, 1.5 to 3ft. or more.

The conventional gas ring of such a burner may comprise a casting or atube, usually of 2 inches or more inside diameter, said tube being bentto form a circular ring having approximately the same inside diameter asthe diameter of the throat of the burner of which the ring forms a part,said ring also having a series of comparatively small, usually drilled,exit ports, spaced at intervals around the inner periphery of the gasring (and hence, essentially, around the periphery of the burner throat)so as to discharge raw gas or a mixture of gas and primary air into theburner throat, for mixture with the combustion air passing through saidthroat. Each of such ports may be drilled to lie in a plane, passingthrough the axis of the burner throat (and of said ring) and directedeither perpendicular to or inclined to said axis, or each of said portsmay be drilled to provide rotation of said exit gas with respect to saidburner throat axis.

Regardless of the specific arrangement of the drilled exit ports theconventional ring-type burner, especially of large throat diameter,provides,with low gas pressure in the ring, insufficient ability for thegas jets leaving said exit ports to penetrate the airstream in theburner throat sufficiently to produce a complete mixture of the gas withsaid air. The net result of such deficiencies often is poor combustionefficiency (i.e., an amount of air required substantially in excess ofthe theoretical i.e. stoichiometric air requirements for completecombustion) and even with a large amount of such excess air, there maybe pulsation, or vibration of the furnace being fired, instability ofignition and sometimes the complete loss thereof.

The present invention can readily be applied to an existing gas ringhaving the usual drilled exit ports or can be used in new constructionwith or without any such drilled exit ports in the ring. The inventioncomprises a series of tubes or fingers mounted at spaced intervalsaround the inner periphery of the gas ring and threaded or otherwisesuitably attached to the inner periphery thereof, and extending asubstantial distance, more or less radially, toward the axis of saidring (and burner throat), but with the axis of each finger lying in themost advantageous specific direction with respect to said ring axis. Thenet result is that, regardless of the specific arrangement of the gasexit port or ports, of each finger, the gas when ejected is much closerto the burner throat axis, and farther within the airstream within theburner throat than would have been possible with the conventionaldrilled hole construction.

Individual fingers may have their form or exit port areas soproportioned as to vary, if desired, the volume of gas injected intovarious areas of the burner throat cross section or periphery so as tocompensate for any unequal distribution of air within said burnerthroat.

More specifically in accordance with the present invention the gasdischarge openings of the gas ring are formed at least in part by aseries of elongated nozzles or fingers which extend in general radiallyinwardly toward the axis of said burner throat from the inner peripheryof the gas ring and have gas discharge openings disposed on at least oneside of each of said fingers or nozzles.

Each of the discharge openings in a finger is so disposed tha the gas isdischarged substantially as an elongated sheet in a plane passingthrough the center of the gas ring tube or at an angle thereto towardthe burner throat. The portion of the finger opposite to the openingserves as a shield for the discharged gas and also introduces turbulenceinto the flow of combustion air to improve the combustion and flamestability of the gaseous fuel, or of the liquid fuel at the burnerthroat if the latter fuel is being used.

Each of said fingers may lie in a common plane perpendicular to theburner throat axis and passing through the center of the tube formingthe gas ring, in which case each finger may either be truly radial orhave its axis inclined to a radius.

Similarly each finger may have its axis in a separate radial planepassing through the burner throat axis with the axis of each fingerinclined to said throat axis. Also the axis of each finger may beinclined not only to said throat axis but also to a radial plane passingthrough said axis.

Such fingers, of course, can be used either in connection with an airregister having curved vanes causing the air to rotate as it passesthrough the burner throat or in connection with an air register havingradial vanes, which will result in substantially axial flow as the airpasses through such throat. They also may be, used alone or inconjunction with conventional gas exit orifices formed in said ringitself or with short spuds carried by said ring and spaced around theinner periphery of said ring.

Regardless of the type of air register it should be noted that the gasdischarge from each finger, regardless of the specific a type ofdischarge port, is substantially from the side of each such finger,rather than axially therefrom, so that each finger might be said todischarge a sheet of gas with maximum surface exposure to the air insaid throat, rather than a jet of gas with much less exposure. Maximumsurface exposure of gas to air tends to promote more thorough mixing ofthe two.

The distribution of air among a group of burners firing a given furnaceand the distribution of air across a given burner throat, both tend tobe imperfect in practice and such maldistribution is always difficultand many times impossible to correct. The finger design retains theadvantages of the ring-type burner while making it possible by adjustingthe position or discharge port area of individual fingers to put the gaswhere the air is to compensate for such maldistribution of air.

In addition to the basic advantages of greater gas penetration into theair in the burner throat and ready change of port conformation onshutdown, a finger with its large flow area is much less susceptible toplugging by any foreign material in the gas being burned than therelatively small drilled exit ports.

Such fingers when suitably used in a combination burner for oil or gasin which the oil is conventionally injected by an atomizer positionedalong the burner throat axis as shown in FIG. ll, not only do notinterfere with the combustion process when oil rather than gas is beingburned, but improve such combustion due to the fact that said fingersact in conjunction with the conventional oil burner diffuser or flamecone to further improve the mixing of the oil spray with the air in theburner throat. This permits operation with a lesser amount of air inexcess of theoretical combustion requirements and also assists saiddiffuser in stabilizing the oil flame under widely varying conditions.

The nature of the invention will be better understood from the followingdescription taken in connection with the accompanying drawings in whichcertain specific embodiments have been set forth for purposes ofillustration.

in the drawings:

FIG. I is a longitudinal view partly in section of a fuel burnerembodying the invention;

FIG. 2 is a section taken on line 2-2 of FIG. I of a portion of the gasring showing the discharge fingers with a part of the ring broken awayfor clarity;

FIG. 3 is a section taken on the line 3-3 of FIG. 2;

FIGS. 4 and 5 are views similar to FIGS. 3 and 2 respectivelyillustrating a finger having a single side opening;

FIGS. 6 and 7 are views similar to FIGS. 3 and 2 respectivelyillustrating fingers having a pair of side discharge openings;

FIGS. 8 and 3 are views similar to FIGS. 3 and 2 respectively showingfingers having a further form of gas discharge open FIGS. 10 and 11 areviews similar to FIGS. 2 and 3 respectively showing a type of adjustabletwo-piece finger;

FIG. 12 is a view similar to FIG. 3 but in partial section illustratinga further type of adjustable two-piece finger; and

FIG. 13 is a section taken on the line 13-13 of FIG. 12 but showing theparts in a different angular relation.

Referring to the drawings more in detail the invention is shown asapplied to a fuel burner firing into the combustion chamber of a furnacehaving a wall 10 with a burner throat opening 11 formed by a ring ofthroat tiles 12. A front wall 13 is spaced from the furnace wall 10 toform a plenum chamber 14 therebetween. The burner elements include anair register 15 having a front plate 16 secured to the front wall 13 andregistering axially with a burner tube 17 having a rear flange l8 boltedto a plate 19 secured to the wall 10. A gas ring 20 of the usual typefor supplying gaseous fuel is secured between the flange 18 and theplate 19 adjacent the throat opening 11. A fuel barrel ZI of the typecarrying gaseous liquid or pulverized fuel extends axially through theair register 15 with an atomizing tip 22 disposed axially within theburner throat 11.

An igniter tube 25 extends from the front wall 13 to the burner tube 17at a point near the rear flange l8 and at an appropriate angle to theaxis of the burner throat.

A gas pipe 26 having an igniter 27 at its rearward end extends throughthe tube 25 and is so arranged that the igniter can be advanced orretracted therein. When in use the igniter 27 is advanced so that theflame therefrom projects into the path of the combustible air and fuelmixture in the zone of the atomizer tip 22 or of the fingers 30.

In FIGS. 2 and 3 the gas ring 20 is shown as having a plurality ofdischarge fingers or nozzles 30 extending inwardly a substantialdistance from its inner periphery toward the axis of the ring and also aseries of conventional gas exit orifices 68 located peripherally betweenadjacent fingers. Each finger 30 comprises a length of pipe which isthreaded or otherwise secured in the gas ring with a bore 31communicating with the interior of the gas ring. The depending end 32 ofeach finger 30 is chamfered, that is, cut at an angle to the axis of thefinger to provide a tapered end opening 33 from which the gas isdischarged into the airstream of the burner. In the embodiment shown theopening 33 is directed axially toward the burner throat so that the gasis discharged in a sheet as long as the opening 33 in the direction ofthe throat. It is to be understood, however, that the opening 33 may bedirected in the plane through the center of the gas ring tube or at anydesired angle thereto so as to impart rotation to the gas stream as itis discharged and to direct the stream at an angle across the stream ofcombustion air passing through the burner tube 17 to the throat.

In FIGS. 4 and 5 the elongated nozzles or fingers 35 are secured to thegas ring 20 and extend inwardly therefrom similarly to the fingers 30.Each finger 35 has an axial bore 36 and is formed with an arcuate cut 37on one side forming an opening 38 for the discharge of gas. The end 39of each finger 35 may have an end wall 39a to close the end of thefinger or the end may be open for the discharge of gas as desired.

As in the case of the fingers 30 above described the opening 38 may bedirected toward the burner throat or at any desired angle thereto. Theoperation is similar to that above described.

In FIGS. 6 and 7 the finger 40 is similar to the finger 35 abovedescribed and is similarly disposed in the gas ring. The finger 40 isformed with two or more out out portions or openings 41 spaced along itslength which are shown as formed on the same side of the finger but mayhowever be angularly displaced about the axis of the finger with respectto each other for producing a fan-shaped discharge. The fingers 40 mayhave an end wall 42 to form a closed end or the end may be open asdesired.

In this embodiment the operation is similar to that of FIGS. 4 and 5except that the gas is discharged over a greater radial distance and maybe angularly spread for improving its distribution in the airstream.

In FIGS. 8 and 9 the fingers 45 are similar to the fingers 30 of FIGS. 2and 3 and are similarly disposed in the gas ring. The fingers 45 areformed with a straight axial cut 46 extending from the inward end 47 ofthe finger toward the periphery of the gas ring to form an elongatedopening 43 for the lateral discharge of gas into the airstream. Thesefingers have an end wall 49 but this end wall may be omitted if desiredto permit gas to be discharged radially as well as laterally. Theoperation is otherwise similar to that of fingers 30 above described.

In FIGS. 10 and 11 fingers 50 are shown as composed of an outer member511 secured to the gas ring in the manner above described and an innersleeve 52 which is slidable within the fixed member 51. The fixed member51 is formed with a chamfered cut 53 at its inward end and the sleeve 52is formed with a similar chamfered cut 54 at its outer end 55. The cuts54 and 53 are so disposed that the effective opening is adjusted byvarying the relative angular and axial positions of the sleeve 52 andthe member 51. The sleeve 52 may be secured in adjusted position by asetscrew 56 and may have an end wall 52a to form a closed end or the endmay be open as desired.

This embodiment provides for adjustment of the axial length as well asthe circumferential width of the discharge opening.

In FIGS. 12 and 13 the fingers 60 are formed by an outer fixed member 61similar to FIG. 3, which is secured in the gas ring as above describedand an inner adjustable sleeve 62 similar to FIG. 8, which telescopeswithin the outer member 61 and projects beyond the inward end thereof.The projecting end 63 of the sleeve 62 if formed with a straight axialcut 64 forming an opening 65. The inward end of sleeve 62 may have anend wall 63a to form a closed endor the end may be open as desired.

The axial length of the exposed portion of the opening 65 may be variedby axial adjustment of the sleeve 62 and the angular position of thedischarge opening may be adjusted by varying the rotational position ofthe sleeve 62 in the outer member 61. The sleeve 62 may be held inadjusted position by a setscrew 67.

FIG. 12 shows the opening 65 extending axially toward the burner throatand FIG. 13 shows the opening as disposed at an angle thereto.

As a specific example the fingers of any type may extend inwardly for adistance corresponding to about a third of the inner radius of the gasring or in general the fingers may have a length such that a circleconcentric with the gas ring and tangent to the inward ends of thefingers has a diameter of from 60 to percent of the diameter of theinner periphery of the gas ring. This distance may however be variedaccording to the requirements of a particular burner.

While several forms of finger openings have been shown for purposes ofdisclosure it is obvious that the shape and size of the opening and therelative angular position thereof may be varied according torequirements.

Iclaim:

l. A fuel burner comprising a burner tube through which a stream of airfor combustion flows, a gas ring having its inner periphery disposed inregistration with and forming a portion of said burner tube and havingperipherally spaced openings communicating with the interior of saidburner tube and adapted to introduce fuel gas directly into saidairstream in said tube, and a set of tubular fingers carried by said gasring with their outer ends communicating with at least some of said gasring openings and with their inner ends extending inwardly into theairstream in said burner tube, said fingers having side openings spacedinwardly of said burner tube and disposed to discharge gas from said gasring directly into the airstream in said tube for mixing therewith, thesides of said tubular fingers opposite said side openings being disposedto form shields to prevent said airstream from interfering with thedischarge of gas from said side openings into the airstream.

2. A fuel burner as set forth in claim 1 in which said fingers are incommunication with certain of said discharge openings and others of saiddischarge openings are disposed to introduce gas from said ring directlyinto said airstream at the inner periphery of said ring.

3. A fuel burner as set forth in claim 1 in which said fingers eachcomprise a pair of telescoping members at least one of which has a sideopening in a'position to be varied in accordance with the telescopingposition of said members.

4. A fuel burner as set forth in claim 3 in which side openings areformed in both of said members.

5. A fuel burner as set forth in claim I in which said fingers are incommunication with each of said discharge openings.

6. A fuel burner as set forth in claim I in which a circle tangent tothe inward ends of said fingers and concentric with the central openingof said gas 'ring has a diameter varying between 60 percent and percentof the diameter of said central opening.

1. A fuel burner comprising a burner tube through which a stream of airfor combustion flows, a gas ring having its inner periphery disposed inregistration with and forming a portion of said burner tube and havingperipherally spaced openings communicating with the interior of saidburner tube and adapted to introduce fuel gas directly into saidairstream in said tube, and a set of tubular fingers carried by said gasring with their outer ends communicating with at least some of said gasring openings and with their inner ends extending inwardly into theairstream in said burner tube, said fingers having side openings spacedinwardly of said burner tube and disposed to discharge gas from said gasring directly into the airstream in said tube for mixing therewith, thesides of said tubular fingers opposite said side openings being disposedto form shields to prevent said airstream from interfering with thedischarge of gas from said side openings into the airstream.
 2. A fuelburner as set forth in claim 1 in which said fingers are incommunication with certain of said discharge openings and others of saiddischarge openings are disposed to introduce gas from said ring directlyinto said airstream at the inner periphery of said ring.
 3. A fuelburner as set forth in claim 1 in which said fingers each comprise apair of telescoping members at least one of which has a side opening ina position to be varied in accordance with the telescoping position ofsaid members.
 4. A fuel burner as set forth in claim 3 in which sideopenings are formed in both of said members.
 5. A fuel burner as setforth in claim 1 in which said fingers are in communication with each ofsaid discharge openings.
 6. A fuel burner as set forth in claim 1 inwhich a circle tangent to the inward ends of said fingers and concentricwith the central opening of said gas ring has a diameter varying between60 percent and 80 percent of the diameter of said central opening.